/* vi: set sw=4 ts=4: *//* * Mini nslookup implementation for busybox * * Copyright (C) 1999,2000 by Lineo, inc. and John Beppu * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */#include <ctype.h>#include <errno.h>#include <stdio.h>#include <string.h>#include <stdlib.h>#include <netdb.h>#include <sys/socket.h>#include <sys/types.h>#include <netinet/in.h>#include <resolv.h>#include <arpa/inet.h>#include "busybox.h"/* |  I'm only implementing non-interactive mode; |  I totally forgot nslookup even had an interactive mode. | |  [ TODO ] |  + find out how to use non-default name servers *//* only works for IPv4 */static int addr_fprint(char *addr){	u_int8_t split[4];	u_int32_t ip;	u_int32_t *x = (u_int32_t *) addr;	ip = ntohl(*x);	split[0] = (ip & 0xff000000) >> 24;	split[1] = (ip & 0x00ff0000) >> 16;	split[2] = (ip & 0x0000ff00) >> 8;	split[3] = (ip & 0x000000ff);	printf("%d.%d.%d.%d", split[0], split[1], split[2], split[3]);	return 0;}/* takes the NULL-terminated array h_addr_list, and * prints its contents appropriately */static int addr_list_fprint(char **h_addr_list){	int i, j;	char *addr_string = (h_addr_list[1])		? "Addresses: " : "Address:   ";	printf("%s ", addr_string);	for (i = 0, j = 0; h_addr_list[i]; i++, j++) {		addr_fprint(h_addr_list[i]);		/* real nslookup does this */		if (j == 4) {			if (h_addr_list[i + 1]) {				printf("\n          ");			}			j = 0;		} else {			if (h_addr_list[i + 1]) {				printf(", ");			}		}	}	printf("\n");	return 0;}/* print the results as nslookup would */static struct hostent *hostent_fprint(struct hostent *host, int is_server){	char *format;	if (is_server) {		format = "Server:     ";	} else {		format = "Name:       ";	}	if (host) {		printf("%s%s\n", format, host->h_name);		addr_list_fprint(host->h_addr_list);	} else {		printf("*** Unknown host\n");	}	return host;}/* changes a c-string matching the perl regex \d+\.\d+\.\d+\.\d+ * into a u_int32_t */static u_int32_t str_to_addr(const char *addr){	u_int32_t split[4];	u_int32_t ip;	sscanf(addr, "%d.%d.%d.%d",		   &split[0], &split[1], &split[2], &split[3]);	/* assuming sscanf worked */	ip = (split[0] << 24) |		(split[1] << 16) | (split[2] << 8) | (split[3]);	return htonl(ip);}/* gethostbyaddr wrapper */static struct hostent *gethostbyaddr_wrapper(const char *address){	struct in_addr addr;	addr.s_addr = str_to_addr(address);	return gethostbyaddr((char *) &addr, 4, AF_INET);	/* IPv4 only for now */}/* lookup the default nameserver and display it */static inline void server_print(void){	struct sockaddr_in def = _res.nsaddr_list[0];	char *ip = inet_ntoa(def.sin_addr);	hostent_fprint(gethostbyaddr_wrapper(ip), 1);	printf("\n");}/* naive function to check whether char *s is an ip address */static int is_ip_address(const char *s){	while (*s) {		if ((isdigit(*s)) || (*s == '.')) {			s++;			continue;		}		return 0;	}	return 1;}/* ________________________________________________________________________ */int nslookup_main(int argc, char **argv){	struct hostent *host;	if (argc < 2 || *argv[1]=='-') {		show_usage();	}	res_init();	server_print();	if (is_ip_address(argv[1])) {		host = gethostbyaddr_wrapper(argv[1]);	} else {		host = gethostbyname(argv[1]);	}	hostent_fprint(host, 0);	return EXIT_SUCCESS;}/* $Id: nslookup.c,v 1.28 2002/04/27 04:03:59 andersen Exp $ */